There are a number of other conditions that present with similar features to chronic urticaria and angioedema.
Conditions that can present similarly to chronic urticaria are listed below.
Chronic urticarial vasculitis is associated with low or normal complement levels and confusingly can be a primary autoimmune disorder, or a process secondary to another autoimmune disease, like lupus. Urticarial vasculitis lesions sometimes resolve quickly but can last for several days. A lesion biopsy can distinguish between CU and chronic urticarial vasculitis. Painful or burning lesions suggest urticarial vasculitis, with raised lesions that don’t blanch, and may leave hyperpigmented areas in place of resolved lesions. Hepatitis B and C can cause urticarial vasculitis.
Swelling of the upper eyes can be mistaken for angioedema, but in some people may be a symptom of thyroid ophthalmopathy, thyroid driven eye disease. Development of urticaria for during pregnancy is not unusual. Cyclical urticaria can be from autoimmune progesterone dermatitis. Episodes of angioedema with accompanying weight gain can be caused by Gleich syndrome (episodic angioedema with eosinophilia).
Cutaneous mast cell patients demonstrate a variety of urticaria-like lesions, including urticaria pigmentosa, mastocytomas and telangiectasia macularis eruptive perstans. Mast cell activation syndrome can also cause angioedema and urticaria, but generally these are not the only symptoms.
Erythema multiforme looks like urticaria but is often due to viral infections, mycoplasma infections or some medications. Bullous pemphigoid can initially present with hive-like welts or small plaques that do not always blister in early disease. Swelling of the lips in the absence of eczema can indicate cheilitis granulomatosa.
Schnitzler syndrome can cause non-itching hives that exclude the face, bone pain and intermittent fevers. These patients also have IgM or IgG monoclonal gammopathy.
Angioedema in the absence of urticaria is rare. There are a few conditions that can cause it.
Hereditary angioedema (HAE) is caused by C1 esterase inhibitor deficiency (in type I, 80%-85% of cases); or dysfunction (in type II, 15-20%). People with HAE do not have coincident urticaria. HAE is inherited in an autosomal dominant pattern, but up to ¼ of patients develop the condition through spontaneous mutation rather than through inheritance of the gene. About 40% of patients have their initial attacks before the age of 5.
Acquired angioedema (AAE) is caused by antibodies to C1 esterase inhibitor, which is usually caused by cancers of B cells. AAE is more likely to develop in older patients (usually fourth decade of life or later) and family history of angioedema is generally absent. AAE is also more likely to develop when an autoimmune disease or proliferative blood disorder is present.
Angioedema associated with these conditions can affect any part of the body, including limbs and abdomen. Patients with abdominal angioedema are often misdiagnosed as having an “acute” abdomen that requires surgical intervention. It is not unusual for patients to present initially only with abdominal swelling. Both HAE and AAE have a number of common triggers, including infection, emotional or physical stress. or trauma. Importantly, they are not caused directly by histamine and other mast cell mediators and as such are not responsive to antihistamines and corticosteroids.
There is also a form of angioedema specifically induced by treatment with ACE inhibitors. It can be relieved by discontinuing ACE inhibitor therapy. Idiopathic angioedema can also occur in the absence of urticaria but is more likely to respond to prophylactic antihistamine use than HAE or AAE.
Edited to add: I removed the following line from the first HAE paragraph: “Type III is estrogen mediated and only found in adult women.” This statement is inaccurate, I mistakenly included i, as I had originally noted it when reading a paper from 2007. I am doing a follow up post on HAE that will elaborate further on the different subtypes and treatment. Many thanks to the reader who caught it!
Jonathan A. Bernstein, et al. The diagnosis and management of acute and chronic urticaria: 2014 update. J Allergy Clin Immunol Volume 133, Number 5.
Zuberbier T, Maurer M. Urticaria: current opinions about etiology, diagnosis and therapy. Acta Derm Venereol 2007;87:196-205.
Ferdman, Ronald M. Urticaria and angioedema. Clin Ped Emerg Med2007; 8:72-80.
Kanani, Amin, et al. Urticaria and angioedema. Allergy Asthma and Clinical Immunology 2011, 7(Suppl 1):S9.